Patent EP0209140A2 successfully refreshed from Google Patents.
EP0209140A2
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A method of measuring a minute flying height of an object and a magnetic disk apparatus
Assignee: Toshiba Corp
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Filing: 1986-07-17
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Granted: —
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Expires: 2006-07-17
Abstract
Abstract In a magnetic disk apparatus according to the present invention, a slider has a sliding surface (K) and a reflecting surface (M). The height of the reflecting surface (M) from the magnetic disk (1) is greater than that of the sliding surface (K) from the disk (1), when the slider (6) flys above the disk (1), so that there exists a minute difference in level between the sliding surface (K) and the reflecting surface (M). The flying height of the sliding surface (K) of the slider (6) from the magnetic disk is measured. When the magnetic disk (1) is rotated, the slider (6) flys from the disk (1). In this state, reference flying height, i.e., the flying height of the reflecting surface (M) from the magnetic disk (1) is measured by the optical interference process. Then, the minute difference is subtracted from the measured reference flying height to obtain the flying height of the sliding surface (K) of the slider (6) from the magnetic disk (1). According to the invention, even if the minimum flying height of the sliding surface (K) of the slider (6) is shorter than 0.1 micrometer, the measurement can be effected by the optical interference process. In general, moreover, a minute flying height between a fixed datum plane and an object flying above the datum plane can be measured accurately.
Inventors
- 👤 Masahiro Patent Division Kubo
- 👤 Yasuo Patent Division Ohtsubo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 15:23
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B33/00; G11B33/10
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
138 words
A method of measuring a flying height of an object (6, 60, 70), the object (6, 60, 70) having first and second surfaces (K, K1, K2, K3 71, M, 72, 73) opposite to a datum plane (1), and the flying height being defined as a height between the first surface (K, K1, K2, K3, 71) and the datum plane (1) and being shorter than a reference height between the second surface (M, 72, 73) and the datum plane (1) when the object (6, 60, 70) is flied above the datum plane (1), a predetermined minute difference (s) existing between the flying height and the reference height, said method characterized by comprising steps of: measuring the reference height by an optical interference process; and subtracting the predetermined minute difference from the measured reference height to obtain the flying height.
Claim 2
Independent Claim
138 words
A method of measuring a flying height of an object (6, 60, 70), the object (6, 60, 70) having first and second surfaces (K, K1, K2, K3 71, M, 72, 73) opposite to a datum plane (1), and the flying height being defined as a height between the first surface (K, K1, K2, K3, 71) and the datum plane (1) and being shorter than a reference height between the second surface (M, 72, 73) and the datum plane (1) when the object (6, 60, 70) is flied above the datum plane (1), a predetermined minute difference (s) existing between the flying height and the reference height, said method characterized by comprising steps of: measuring the reference height by an optical interference process; and subtracting the predetermined minute difference from the measured reference height to obtain the flying height.
Claim 3
Independent Claim
137 words
A method of measuring a flying height of a slider (6, 60, 70), the slider (6, 60, 70) having a sliding surface (K, K1, K2, K3, 71) and a reflecting surface (M, 72, 73) opposite to a magnetic disk (1), and the flying height being defined as a height between the sliding surface (K, K1, K2, K3, 71) and the disk (1) and being shorter than a reference height between reflecting surface (M, 72, 73) and the disk (1) when the slider (6, 60, 70) is flied above the disk (1), a predetermined minute difference (s) existing between the flying height and the reference height, said method characterized by comprising steps of: measuring the reference height by an optical interference process; and subtracting the predetermined minute difference from the measured reference height to obtain the flying height.
Claim 4
Independent Claim
137 words
A method of measuring a flying height of a slider (6, 60, 70), the slider (6, 60, 70) having a sliding surface (K, K1, K2, K3, 71) and a reflecting surface (M, 72, 73) opposite to a magnetic disk (1), and the flying height being defined as a height between the sliding surface (K, K1, K2, K3, 71) and the disk (1) and being shorter than a reference height between reflecting surface (M, 72, 73) and the disk (1) when the slider (6, 60, 70) is flied above the disk (1), a predetermined minute difference (s) existing between the flying height and the reference height, said method characterized by comprising steps of: measuring the reference height by an optical interference process; and subtracting the predetermined minute difference from the measured reference height to obtain the flying height.
Claim 5
Dependent Claim
52 words
The method according to claim 2, further comprising a step of measuring the flying height of a magnetic head (5) from the magnetic disk (1) on the basis of the flying height of the sliding surface (K, K1, K2, K3, 71) of the slider (6, 60, 70) from the magnetic disk (1).
Claim 6
Dependent Claim
157 words
A magnetic disk apparatus which comprises a magnetic disk (1) rotated by a motor (3) and a magnetic head (5) for writing in and reading information from the magnetic disk (1), characterized by further comprising: a slider (6, 60, 70) fixing the magnetic head (5) and movable together therewith above the magnetic disk (1), said slider (6, 60, 70) having a sliding surface (K, K1, K2, K3, 71) adapted to fly from the magnetic disk (1) as the magnetic disk (1) rotates, and a reflecting surface (M, 72, 73), the height of the reflecting surface (M, 72, 73) from the disk (1) being greater than that of the sliding surface (K, K1, K2, K3, 71) from the disk (1), when the slider (6, 60, 70) flys above the disk (1), so that there exists a predetermined minute difference (s) in level between the sliding surface (K, K1, K2, K3, 71) and the reflecting surface (M, 72, 73).
Claim 7
Dependent Claim
157 words
A magnetic disk apparatus which comprises a magnetic disk (1) rotated by a motor (3) and a magnetic head (5) for writing in and reading information from the magnetic disk (1), characterized by further comprising: a slider (6, 60, 70) fixing the magnetic head (5) and movable together therewith above the magnetic disk (1), said slider (6, 60, 70) having a sliding surface (K, K1, K2, K3, 71) adapted to fly from the magnetic disk (1) as the magnetic disk (1) rotates, and a reflecting surface (M, 72, 73), the height of the reflecting surface (M, 72, 73) from the disk (1) being greater than that of the sliding surface (K, K1, K2, K3, 71) from the disk (1), when the slider (6, 60, 70) flys above the disk (1), so that there exists a predetermined minute difference (s) in level between the sliding surface (K, K1, K2, K3, 71) and the reflecting surface (M, 72, 73).
Claim 8
Dependent Claim
22 words
The apparatus according to claim 4, characterized in that the maximum of said minute difference (S) ranges from 0.1 to 2 micrometers.
Claim 9
Dependent Claim
20 words
The apparatus according to claim 4, characterized in that said reflecting surface (M, 72, 73) is provided on a slant.
Claim 10
Dependent Claim
26 words
The apparatus according to claim 4, characterized in that said reflecting surface (M, 72, 73) is adjacent to the sliding surface (K, K1, K2, K3, 71).
Claim 11
Dependent Claim
27 words
The apparatus according to claim 4, characterized in that said reflecting surface (M, 72, 73) is located in the central portion of the slider (6, 60, 70).
Claim 12
Dependent Claim
64 words
The apparatus according to claim 4, characterized in that a ridge (15, 17) is formed on that face of said slider opposed to the magnetic disk (1), said ridge (15, 17) extending in the rotating direction of the magnetic disk (1), and said reflecting surface (M, 72, 73) is formed beside the ridge (15, 17) so as to extend along the ridge (15, 17).
Claim 13
Dependent Claim
17 words
The apparatus according to claim 4, characterized in that said magnetic head (5) is a thin-film head.
Claim 14
Dependent Claim
23 words
The apparatus according to claim 4, characterized in that said magnetic disk (1) includes a perpendicular magnetic recording medium as a recording layer.
Claim 15
Dependent Claim
74 words
The apparatus according to claim 4, characterized in that said slider is a negative-pressure slider, and a recess is formed on one side so that the slider (70) has a sliding surface (71) and a specular negative-pressure producing surface (72) which are opposed to said disk (1), and in that the negative-pressure producing surface (72) is polished to act as the reflecting surface used to measure a flying height of the sliding surface (71).
Claim 16
Dependent Claim
35 words
The apparatus according to claim 12, characterized in that said negative-pressure producing surface (72, 73) is a surface parallel to or slanted at an angle to the sliding surface (71) of the negative-pressure slider (70).
References Cited (Backward Citations)
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